The present invention relates in general to a portable air purification device for closed environments containing polluted air, and more particularly, to a high capacity mobile air purifier which is designed to
address the problems and concerns of patients and health care personnel in environments where communicable diseases can be transmitted via the airborne route.
Air purification devices have been widely used in various applications from pollen and smoke containing polluted air at work places and the like, to hazardous microbial airborne particles which include the tuberculosis bacilla and other infectious respiratory organisms at hospitals and the like. Tuberculosis, in particular, has become a nationwide dilemma. Recent outbreaks of new drug resistant strains have surfaced in many locations. For example, last year New York State had a 31% increase in active cases, while New York City has experienced more than a doubling of their tuberculosis cases in the last decade. It is estimated that one million persons are infected with HIV which is a contributing factor to the current tuberculosis epidemic. Recent reports state that some ten million Americans are currently infected with tuberculosis.
The Center for Disease Control in Atlanta, Ga. recommends the containment of airborne tuberculosis bacteria by the use of High Efficiency Particulate Air (HEPA) filtration, ventilation or exhaust, dilution, ultraviolet lamps or isolation rooms. Each of these recommended procedures, in and of themselves, suffer from a number of drawbacks. For example, HEPA filtration is very costly and can only be provided by placing HEPA filters in the existing ventilation system which may not serve the infected area. Most hospitals were not designed to accommodate the HEPA filters required for the current infectious epidemics. The hospitals ventilation systems frequently cannot be retrofitted to accommodate HEPA filters since they are must larger, heavier and have a much higher resistance than current filters being used.
Ventilation requires exhausting 100% of the contaminated air to the surrounding atmosphere and replacing same with make-up air which has to be filtered and either cooled or heated. Due to the large volume of air required to be exhausted, it is frequently both noisy and uncomfortable for the patient. In addition, it is improper to exhaust contaminated air within 25 feet of air intakes and within range of other humans or animals.
Dilution, on the other hand, requires that the contaminated air within a room be mixed with other air that is either filtered or is made up of outside air. In many areas of the country, the outside air is more severely polluted than the inside air and must be prefiltered prior to being introduced to the indoor environment. Dilution although effective in reducing the percentage of airborne tuberculosis bacteria is not 100% effective. In this regard, a sufficiently high level of tuberculosis bacteria will remain present which can infect a human present within the room.
The use of ultraviolet lamps or ultraviolet radiation has been recognized and utilized for many years in health care environments. However, unless there is a constant air flow within a room over the ultraviolet lamps, vast areas of the room are not disinfected. In addition, the further away one gets from the ultraviolet lamps, the lower the disinfection rate, as well as there being stagnant areas within the room which will be effectively untreated. It is also known that the ultraviolet lamps have to be shielded from patients who cannot be directly exposed to the light, as it affects both ones eyes and skin. These, as well as other drawbacks make the use of ultraviolet lamps or ultraviolet radiation ineffective as a sole procedure for controlling tuberculosis bacteria.
Isolation or negative pressure rooms have been found to be the best defense since they restrict the patient and contamination from spreading. However, most hospitals are not equipped with enough isolation rooms to accommodate the huge increase of patients being admitted. As any one of these procedures recommended by the Center for Disease Control possess individual drawbacks, there is an unsolved need for a self-contained portable room air treatment apparatus for the effective removal of hazardous microbial airborne particles to provide a safe environment for patients and medical staff.